Taken together, we propose that the improved leukemia-free survival in AML patients treated with HDC plus IL-2 might, at least to some extent, result from the induced expansion of CD56bright NK cells reconstituting a fresh pool of immunocompetent NK cells including the three described NK cell subsets and additionally supporting and maintaining a high expression level of activating receptors and a high capacity of IFN-γ production and degranulation capability. This evidence concerns the gene IL2 and leukemia.